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How to detect if a function is called as constructor?

...oking at the ECMAScript 3rd edition spec, the steps taken when new x() is called are essentially: Create a new object Assign its internal [[Prototype]] property to the prototype property of x Call x as normal, passing it the new object as this If the call to x returned an object, return it, otherw...
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mongodb: insert if not exists

... has built-in support for this. Pass an extra parameter to your update() call: {upsert:true}. For example: key = {'key':'value'} data = {'key2':'value2', 'key3':'value3'}; coll.update(key, data, upsert=True); #In python upsert must be passed as a keyword argument This replaces your if-find-els...
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What is the use of interface constants?

...attern is a poor use of interfaces. That a class uses some constants internally is an implementation detail. Implementing a constant interface causes this implementation detail to leak into the class's exported API. It is of no consequence to the users of a class that the class implements a constant...
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ASP.NET MVC - Attaching an entity of type 'MODELNAME' failed because another entity of the same type

...'Modified'. Before changing the state, the state is set to 'Detached' but calling Attach() does throw the same error. I'm using EF6. ...
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What does `:_*` (colon underscore star) do in Scala?

...tes: MetaData, scope: NamespaceBinding, child: Node*) which is called as new Elem(prefix, label, attributes, scope, child1, child2, ... childN) but here there is only a sequence, not child1, child2, etc. so this allows the result sequence to be used as the input to the constru...
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Java Reflection: How to get the name of a variable?

...they are in scope. Perhaps a byte-code engineering library like ASM would allow you to inspect this information at runtime. The only reasonable place I can think of for needing this information is in a development tool, and so byte-code engineering is likely to be useful for other purposes too. ...
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How do I determine if a port is open on a Windows server? [closed]

... there is a difference if you open telnet.exe and then type o host port vs open command line (cmd.exe) and then type telnet host port – Pawel Cioch Jul 21 '15 at 13:42 ...
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How to get the currently logged in user's user id in Django?

...rs = [{user.id: user.get_name()} for user in logged_in_users] # Query all logged in staff users based on id list all_staff_users = CustomUser.objects.filter(is_resident=False, is_active=True, is_superuser=False) logged_out_users = list() # for some reason exclude() would not work co...
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Update multiple rows in same query using PostgreSQL

... This is wrong... You will update all rows, even if it is not '123' nor '345'. You should use WHERE column_b IN ('123','456')... – MatheusOl Sep 14 '13 at 3:54 ...
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Run a Python script from another Python script, passing in arguments [duplicate]

... I believe it's generally preferable to use subprocess.Popen over os.system: docs.python.org/library/subprocess.html#replacing-os-system. – Katriel Sep 23 '10 at 20:15 ...